> For the complete documentation index, see [llms.txt](https://gchandra.gitbook.io/data-warehousing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gchandra.gitbook.io/data-warehousing/fundamentals/what-is-a-data-warehouse/current-state-of-the-art.md).

# Current State of the Art

The business world decided as follows.

* A Database should exist just for doing BI & Strategic reports.
* It should be separated from the operational / transaction database for the day-to-day running of the business.
* It should encompass all aspects of the business (sales, inventory, hr, customer service…)
* An enterprise-wide standard definition for every field name in every table.
  * Example: employee number should be identical across DB. empNo, eNo,EmployeeNum.. empID not acceptable.
* Metadata database (data about data) defining assumptions about each field, describing transformations performed and cleansing operations, etc.
  * Example: If US telephone, it should be nnn-nnn-nnnn or (nnn) nnn-nnnn
* Data Warehouse is read-only to its end users so that everyone will use the same data, and there will be no mismatch between teams.
* Fast access, even if it's big data.

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* Operational databases for tracking sales, inventory, support calls, chat, and email. (Relational and NoSQL)
* The Back Office team (ETL team) gathers data from multiple sources, cleans it, transforms it, massages the missing, and stores it in the Staging database.
  * If the phone number is not in the format, then format it.
  * If the email address is not linked to the chat/phone record, read it from the Customer and update it.
* **Staging database**: Working database where all the work is done to the data. It then dumps to the data warehouse, which is visible as “read-only” to end users.
* Data Analysts then build reports using Data Warehouse.

**We are now going back to the original question.**

If all of these things are done right, Amazon's CEO can get the report in less than 30 minutes without interfering with business operations. 👍